SEITENSTETTEN. — Benedictine abbey in the diocese of Sankt Pölten (Lower Austria).
It was founded around 1100 as a house of Regular Canons, but the founder, Count Udalscalco of Stille and Heft, summoned Benedictine monks there in 1112 from the abbey of Göttweig. It had been an independent abbey since 1114. The church was first dedicated in 1116. A school, including an external school, existed there as early as the Middle Ages; but in 1814 a public secondary school was opened, with an attached boarding school, which soon acquired a great reputation. After its suppression by the Nazis (1938–45), it is now fully recovering. The abbey possesses a noteworthy library, a museum (more than 600 paintings), a medal collection, a coin cabinet, and a treasury. It has pastoral care of 14 incorporated parishes.
The present church is Gothic (the choir dates from around 1300; the three naves are earlier, from 1254); but it was partially rebuilt from 1630 onward and completely given a Baroque makeover in 1677. The altars date from 1690–1703; the side chapels are later. The cloister too is a Baroque reconstruction. The convent, already partly renovated from 1630 onward, was transformed and rebuilt according to a grandiose plan by J. Munggenast and J. G. Hayberger between 1719 and 1749. The long façade measures 160 m; it has five courtyards, with the church at the center; the entrance to the monastery has three naves, and the grand staircase has three flights; the two-story library was frescoed by P. Troger (1741); noteworthy are the refectory, with paintings by J. M. Schmidt, and the Marble Hall, with frescoes by Troger. The whole forms a complex typical of the great Austrian Benedictine abbeys.
Among the incorporated parishes, the sanctuary of the Most Holy Trinity at Sonntagsberg (740 m high) deserves mention; a chapel was built there in 1440, a Gothic church in 1490, and it was transformed into a splendid Baroque structure between 1706 and 1717 by the celebrated architects J. Prandtauer and J. Munggenast. The dome contains a grandiose fresco by D. Gran, one of his major works; the interior and furnishings are in the Baroque style; the Treasury is of interest. — Vedi tav. XVII.